Jc,
THE most frequent primary cause of fracture is not fatigue, but overload
from sharp, full lock, parking maneuvers.
The mainly occur in a reverse motion where the wheel is full left (or
right). This can over stress the pin thread root to crack, or break the
arm. Examination of broken parts reveals this failure mode, caused by
poor design of Tiger steering over stress and really poor mechanical
design for pin.
The actual complete failure could be on crack propagation during later
driving loads, so is not recognized as mostly cracked during a previous
full lock turn.
Lots of fixes ranging from higher strength steels, which are subject to
less ductility and more brittleness, and larger in diameters through the
pin and especially at the thread (and poly. Some offered designs are
poorly made, with sharp radiuses at the thread relief. Even if fixed,
the bolts holding the pin to the car are too small, and too close
together, with very little room for spacing, and bolt diameter increases.
Dan Walters has quite a collection of larger pin designs (all with some
need for improvement, and his own greatly improved design, and so does
Tom Hall. Liability issues prevent selling these through clubs, or even
personally, because of our litigious tendencies.
Steve
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Steve Laifman
Editor - TigersUnited.com
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